Magnetic welding and forming

ABSTRACT

Apparatus for driving members toward each other with repulsive magnetic forces and including a magnetic driver, a magnetic coil and a connector secured to either the coil or driver and adapted to be secured to one of the members.

United States Patent Inventor Theodore Joseph Morin, Jr. Needham, Mass.

Appl. No. 737,651

Filed June 17,1968

Patented Feb. 2, 1971 Assignee Industrial Magnetics, Inc. Canton, Mass.

a corporation of Massachusetts MAGNETIC WELDING AND FORMING References Cited UNITED STATES PATENTS 2,280,800 4/1942 Dawson 219/97 3.254,l93 5/1966 Phillips 219/95 3,394,241 7/1968 Sparrow et al 219/5 7X Primary Examiner-J. V. Truhe Assistant Examiner-Hugh D. J aeger Attorney-William W. Rymer, Jr.

ABSTRACT: Apparatus for driving members toward each other with repulsive magnetic forces and including a magnetic driver, a magnetic coil and a connector secured to either the coil or driver and adapted to be secured to one of the members.

l n u n MAGNETIC WELDING AND FORMING This invention relates to magnetic welding, forming and forging.

It is a principal object of the invention to provide apparatus for drawing members together using repulsive magnetic forces. Other objects include providing novel and inexpensive buttwelding apparatus, forging apparatus or apparatus in which no outside forces need be applied and in which the work area may be easily enclosed.

The invention features a magnetic coil, a magnetic driver mounted on one side of the coil for repulsive interaction with the coil, and a first connector secured to either the coil or driver and adapted for securing to one of the members. In preferred embodiments there are featured buttwelding apparatus in which the driver and connector define an annular chamber substantially enclosing the work area, and forging apparatus including a second driver mounted on the other side of the coil.

Other objects, features and advantages will appear from the following description of preferred embodiments of the invention, taken together with the attached drawings thereof, in which:

FlG. l is a sectional view of a buttwelding apparatus embodying the invention; and

FIG. 2 is a sectional view of a forging apparatus embodying the invention.

Referring now to FIG. 1, there is illustrated magnetic welding apparatus 20 including a connecting cylinder 22, a magnetic driver or driving plate 36, and a magnetic and induction heating coil 26, for buttwelding the adjacent axially facing ends ll, 13 of two metal pipes 10, 12 together. Coil 26 is mounted, and centered by, a coil clamp 24 press fitted near the end 13 of pipe 12. Input leads 28 connect the coil to an electrical energy source (not shown) of a type illustrated in the copending application of Peter Dominic Prevett and Theodore Joseph Morin, entitled Conductive Solids Welding Circuitry," Ser. No. 7l7,804,like the present application, assigned to Industrial Magnetics, Inc.

Connecting cylinder 22 comprises an annular pipe clamp 30 press fitted to pipe 10, a cylindrical wall 34 surrounding the work area defined by ends ll, 13 of pipes l0, l2 and extending past coil 26, and a radially extending annular intermediate wall 32 connecting clamp 30 and cylindrical wall 34.

Magnetic driver 36 is attached to the open end of cylindrical wall 34 with fasteners 38 in position closely adjacent but electrically spaced from coil 26. Pipe 12 extends perpendicularly through a central hole 37 in driver 36. The diameter of hole 37 is slightly greater than the outside diameter of pipe 12 to avoid binding.

As illustrated, connecting cylinder or connector 22 and driver 36, in conjunction with pipes 10, 12, define an almost closed (except for the small annulus between driver 36 and pipe 12) chamber surrounding the work area.

In operation, a high frequency current is passed through coil 26 to create a changing magnetic field to inductively heat the adjacent ends of pipes 10, 12. When the pipe ends have been heated to the desired temperature a large transient current pulse is introduced into coil 26. The current pulse in the coil creates a pulsing magnetic field which induces a current in nearby driving plate 36 and a concomitant magnetic field. The two fields repel each other, driving plate 36 away from coil 26 and, thereby, forcing the ends of pipes and 12 together, forming the weld.

FIG. 2 shows a forge apparatus including a hammer 50, an anvil 52, a coil 54, and a main driver 56. The hammer and anvil have opposing die mounts 58.

Coil 54, which provides the pulsed magnetic field in a manner similar to that of the coil of the previous embodiment, has the cross section shown in FIG. 2, bulging slightly inwardly at the center.

Driver 56 includes an outside platelike flange 62 extending beneath the coil and beyond its outside dimension, and a central frustroconical portion 64 extending up into the center of the coil.

Coil 54 is securely mounted on cylindrical supports 66 extending upwardly from a base 67 through holes in flange 62 of driver 56. The driver is supported on springs 68 mounted on spring supports 70, both surrounding supports 66.

The upper portion 51 of hammer 50 is threaded for adjustably supporting the hammer in a threaded central-hole in hammer support plate 72. A lock ring 49 is provided to prevent rotation of the hammer relative to support plate 72.

Support plate .72 is mounted, by nuts 73, on vertical connecting rods 74 which are welded at their lower ends to flange 62 of driver 56.

Anvil 52 has a shape similar to driver 56, including an outer flange portion and frustroconical inner portion 82 extending into the center of coil 54. The outside diameter of portion 80 is approximately equal to that of coil 54. Anvil 52 is supported by guide rods 84 extending from plate 72, to which they are welded through guide bushings 80 in the flange 80 of anvil 52. A stop or head 88 is provided at the lower end of each guide rod 84.

In operation coil 54 is energized by a current pulse as in the previous embodiment. The repulsive forces generated cause driver 56 to move down away from the coil. Hammer 50 follows the motion of the driver because it is connected to it by connecting rods 74 and plate 72. Anvil 52, which acts'as a secondary driver, is moved away from the coil in an upward direction along guide rods 84 by the forces generated when the coil is pulsed.

Hammer and anvil are thus driven together and with appropriate dies in die mounts 58 a workpiece placed between them can be formed.

Other embodiments will occur to those skilled in the art and are within the following claims.

lclaim:

1. Apparatus for buttwelding the adjacent, generally axially facing surfaces of a pair of longitudinally extending members together using repulsive magnetic forces, said apparatus comprising:

a magnetic coil generally surrounding said surfaces;

a magnetic driver for repulsive interaction with said coil;

and,

a connector secured to one of said coil and said driver and including a connector portion adapted to be secured to one of said members, the other of said driver and said coil being intermediate said one and said connector portion whereby movement of said driver and said coil away from each other in response to said repulsive interaction draws said surfaces together.

2. The apparatus of claim 1 including a second connector secured to the other of said coil and said driver and having a second connector portion adapted to be secured to the other of said members.

3. The apparatus of claim 1 in which said connector includes a generally cylindrical wall portion surrounding said axially facing faces of said members.

4. The apparatus of claim 3 in which said connector is secured to said driver.

5. The apparatus of claim 4 in which said driver is generally planar and defines an opening through which one of said members extends in a direction generally perpendicular to said driver, and said connector is secured to the other of said members.

6. The apparatus of claim 4 wherein said connector and said driver provide an annular chamber adapted for enclosing the portions of said members defining said axially facing surfaces.

7. The apparatus of claim 6 wherein said coil is mounted within said chamber. 

1. Apparatus for buttwelding the adjacent, generally axially facing surfaces of a pair of longitudinally extending members together using repulsive magnetic forces, said apparatus comprising: a magnetic coil generally surrounding said surfaces; a magnetic driver for repulsive interaction with said coil; and, a connector secured to one of said coil and said driver and including a connector portion adapted to be secured to one of said members, the other of said driver and said coil being intermediate said one and said connector portion whereby movement of said driver and said coil away from each other in response to said repulsive interaction draws said surfaces together.
 2. The apparatus of claim 1 including a second connector secured to the other of said coil and said driver and having a second connector portion adapted to be secured to the other of said members.
 3. The apparatus of claim 1 in which said connector includes a generally cylindrical wall portion surrounding said axially facing faces of said members.
 4. The apparatus of claim 3 in which said connector is secured to said driver.
 5. The apparatus of claim 4 in which said driver is generally planar and defines an opening through which one of said members extends in a direction generally perpendicular to said driver, and said connector is secured to the other of said members.
 6. The apparatus of claim 4 wherein said connector and said driver provide an annular chamber adapted for enclosing the portions of said members defining said axially facing surfaces.
 7. The apparatus of claim 6 wherein said coil is mounted within said chamber. 